1. Field of the Invention
The present invention relates to a method for self-cleaning a dust collection electrode of an electronic dust collector, an electronic dust collector having a self-cleaning function, and an air conditioner equipped with the electronic dust collector.
2. Description of the Prior Art
Hitherto, as a device for purifying interior air, there has been known a deodorizing equipment. This deodorizing equipment includes a deodorizing catalyst, which adsorbs the odorous components contained in room air such as tobacco smoke to carry out deodorizing air in room. However, such deodorizing equipment has drawback in its inability to remove dust having relatively large particle size such as cotton dust. As a result, such deodorizing equipment has poor air purification capacity. Air purification equipment capable of removing dust such as cotton dust includes an electronic dust collector. An electronic dust collector is equipped with a discharge electrode and a collection electrode. A high voltage applied between these electrodes ionizes the dust and other fine particles contained in the air surrounding the discharge electrode. The ionized particles are attracted to, and adsorbed on, the collection electrode to purify air. In such electronic dust collector, in order to operate the device for a long period of time without maintenance, there has been contrived a self-cleaning type (maintenance-free type), in which the dust collection electrode includes a heater, with which the dust adsorbed to the collection electrode is removed by oxidation and decomposition.
Besides, there is known an air conditioner having an interior unit including an electronic dust collector so as to enhance the function of air conditioner. For example, as shown in Japanese Patent Publication (Unexamined) No. SHO 64-28427, an electronic dust collector is located on the upstream side of the heat exchanger, i.e., between the front grill and the heat exchanger provided on the depth side thereof. This collects the dust contained in the air taken into the apparatus by adsorbed it on the dust collection electrode to effect air cleaning. In this manner, by incorporating the dust collector in the internal unit of the air conditioner, the air conditioner is provided with the added function of air cleaner in addition to the original air conditioning function.
However, in the air conditioner with electronic dust collector as shown in the above publication, because of the provision of the dust collector on the upwind side of the heat exchanger, induction of air is inhibited, thereby lowering the original air conditioning function. In this connection, there has been contrived an air conditioner with electronic dust collector having an electronic dust collector comprising a linear discharge electrode and a planar dust collection electrode provided in the casing of the interior unit on the lee side of the heat exchanger. However, when the dust collector is provided in the casing, a problem of difficulty maintaining the dust collection electrode occurs. To cope with this, in the same manner as in the above electronic dust collector, there has been designed a self-cleaning type (maintenance-free type) air conditioner with electronic dust collector wherein, as a dust collection device. A heater is provided in the dust collection electrode to decompose the dust by oxidation and thereby to remove the dust adsorbed to the dust collection electrode.
However, in such self-cleaning type electronic dust collector and electronic air conditioner with electronic dust collector, there is no consideration on the heater temperature elevation rate or the like. That is, the heater temperature is suddenly elevated during the self-cleaning. Therefore, such a system produces smoke and generates odor. Also, the dust may catch fire.